The present invention relates to a fault tolerant communications system.
In the past, multi-drop communications systems have been known. Such systems may comprise a control system and a plurality of communications nodes communicating with the control system. However, if a failure or fault occurs in such systems, the entire system is rendered inoperable. The fault in the system must be isolated and repaired, thus causing undesirable delays in the system operation. Some attempts have been made to bypass a faulty node under these circumstances, but in these devices it has been necessary to include the bypass circuitry in each of the nodes, thus rendering the system unduly complex and expensive. Typical systems of this sort are disclosed in U.S. Pat. Nos. 3,162,827, 4,254,496, 4,308,613, 4,623,884, 4,575,842, 4,704,713, 4,993,015, 4,991,174, 4,933,940.